Conventionally, there is known a technique in which in a network configuration including a plurality of nodes and a plurality of paths that connect the nodes, costs of a respective plurality of routes are calculated based on information indicating the quality of each node, and a communication route is determined based on the calculated costs.
However, conventional techniques such as that described above merely determine an optimal communication route in a network configuration in the present state. Thus, when time synchronization is achieved between a master node and one or more slave nodes through relay nodes in a network configuration such as that described above, a relay node that causes the reduction of the accuracy of time synchronization cannot be estimated.